Motor protection circuit breaker — SIRIUS Size S2
Ground fault detection is not included, so a separate ground-fault relay or RCD is needed if that protection is required.
Breaking capacity varies with voltage: 50 kA at 240 V AC, 50 kA at 400 V AC, 12 kA at 500 V AC, and 5 kA at 690 V AC. At 400 V, the 25 kA rating (Icu) is the standard for most industrial motor branch circuits — it coordinates with typical upstream MCCB or fuse ratings. The closest peer in the SIRIUS family is the 3RV2023-4DA10, a Size S0 breaker. The S2 (this part) is physically larger — 55 mm wide vs. 45 mm for S0 — and offers higher breaking capacity at 400 V (25 kA vs. typically 15 kA for S0). If the panel was designed around a 3RV2023-4DA10, the S2 will not drop in without rewiring: the terminal capacity differs (M6 screws, 2x 25 mm² max), and the mounting footprint is wider. For a true form-fit-function match, stay with the same Size.
Environmental and installation limits
Operating temperature range is -50 to +60 °C, with temperature compensation active from -20 to +60 °C — the breaker adjusts its thermal trip curve across that span, so no manual derating is needed for ambient variation within that band. Screw-type terminals on the main circuit accept 2x 1–25 mm² or 1x 1–35 mm² solid or stranded copper. Use a Pozidriv size 2 tip with a 5–6 mm shaft diameter. The maximum switching rate at AC-3 duty is 15 operations per hour — adequate for motor starting cycles, not for high-speed jogging.